Device for metal drawing



Jy 18, 1944. P E, FLCWERS v 2,354,005

DEVICE FOR METALv DRAWING Filed oct. .7. '1941 Ei a E 6 ,g W/W////\////f/// www Y 335-. 5 y y /Mm Patented July V18, 1944 DEVICE FORMETAL DRAWING Paul E. Flowers, Mount Gilead, Ohio, asslgnor to TheHydraulic Development Corporation, Inc., *Wilmingtom Del.; a corporationol' Delaware Application October 7, 1941, Serial No. 413,996

4 Claims.

This invention relates to Ametal working and, in particular, to sheetmetal drawing.

It is an object to provide a press in which a single resilient member isadapted simultaneously to perform two functions, namely, to actuateclamping means for holding a sheet metal piece during the shapingoperation and, to actuate a punch or die for shaping the said sheetmetal piece.

It is a still further object to provide a drawing press which is adaptedto selectively vary the clamping pressure for clamping the work ,pieceto be drawn without any changes in the pressing means proper.

These and other objects and advantages of the invention will appear moreclearly from the following specification in connection with theaccompanying drawing, in which:

Figure 1 diagrammatically illustrates, in spaced relationship to eachother, the various elements for carrying out the method according to Theinvention.

Figure 2 shows the various elements of Figure 1 in assembled positionjust prior to the beginning of the actual pressing operation.

Figure 3 illustrates the actual pressing operation of the assembly ofFigure 2.

Figure 4 is a view similar to that of Figure 3. showing a slightmodication for obtaining a diierent clamping pressure on different partsof the Work piece to be shaped.

Figure 5 is a top view of a press bed with differently shaped dies.

General arrangement The assembly for performing the new method of metaldrawing according to the invention comprises substantially a rubber padoperatively connected to the press plunger and adapted,

when the latter is advanced, to exert pressure simultaneously on` a dieor punch which shapes a work piece to be drawn. and also on clampingmeans which hold the work piece during the drawing operation.

Due to the yieldable characteristics of a rubber` pad, the latter whenengaging the clamping means and pressing the same againstthe work pieceyields laterally, while maintaining a predetermined pressure on theclamping means, whereas that portion of the rubber pad engaging the dieor punch presses the latter into the cooperating die supporting the workpiece so as to shape the same.

Structural arrangement marginal portions by clamping means 5, which mayconsist of a single piece or a plurality of parts. 6 designates a punchor die for engagement with the work piece l and which, in cooperationwith the die 3, shapes the `work piece.

The punch or die 6 is advanced intothe die 3 by means of the rubber pad1 arranged in a pad holder 8 which is connected in any desired manner tothe press plunger or press platen 9. 'I'he press plunger or platen 9 maybe reciprocated in any desired manner, either mechanically orhydraulically and may form a. part of any desired standard press.

To perform a drawing operation, the operator places the die 3 on thebolster plate 2, then places the work piece 4 on top of the die 3 andthereafter arranges the clamping means or blankholder 5 on the rimportions of the work piece 4 preferably so thatthe inner edges of theblankholder 5 do not materially protrude toward the inside beyond theinner contour of the die 3.'

Preferably the die 3 and blankholder 5 are provided with aligning means,not shown, for properly locating the blankholder with respect to the die3. If the elements 3, 4 and 5 have been properly arranged, the punch ordie E is placed on top of the work piece 4 within theblankholderoperation, the elements will occupy the position shown inFigure 2.

When further pressure is exerted upon the press plunger or platen 9, therubber pad 'l will pressV the blankholder means 5 firmly against the rimportions of the workpiece d so as to clamp the same between theblankholder means 5 and the die 3. On the other hand, the rubber pad 1conveys pressure to the punch E and advances the same so as to cause thepunch 6 to draw the Work piece 4 in conformity with the inner contour ofthe die 3. The pressure exerted by the rubber pad on the blankholdermeans 5 is such as to allow a slipping of the marginal portions of thework piece to a desired extent, thereby preventing wrinkling of the workpiece during the drawing operation.

The pressure at which the marginal portions of the work piece are heldclamped between the die 3 and blankholder means 5 may be varied in asimple manner by merely decreasing or `increasing the corresponding areaof the blankholder means to which the pressure is conveyed from therubber pad. For instance, with regard to Figure 4, it will be seen thatthe area I0 of the blankholder means I l is larger than the area l2 ofthe blankholder means I I so that the righthand end of the work piece lwill be clamped at a higher pressure than the said work piece.

The assembly shown in the drawing may be used for pressing single partsor for simultaneously pressing also a plurality of parts, for instance,the rubber pad 'l of Figure 3 may be considered integral with the rubberpad of Figure 4 so that Figure 3 constitutes a section along the line3-3 of Figure 5, while Figure 4 may be considered a section along theline 4 4 of Figure 5.

If it is desired to use the press not as a drawing press but merely as aforging press, all that is necessary is to remove the clamping means 5left end of the and to replace the die 3 by a corresponding die.

It is not even necessary to use the punch 6 if the rubber pad 1 is used.Otherwise, the rubber pad 1 and punch l may be replaced by acorresponding punch connected to the press plunger or platen S.

It will be understood that ,I desire to comprehend within my inventionsuch modifications as come within the scope of the claims and theinvention. Y

^ Having thus fully described my invention, what I claim as new anddesire to secure by Letters Patent, is:

l. In a press, a female die having. a cavity and arranged to support ametal sheet on its upper surface, a clamping member overlying the uppersurface of said die and adapted to clamp the metal sheet against thesurface of said die, a. substantially rigid male die member fittingwithin the clamping member and of such size and shape as tosubstantially iill the space within thei'emale die, and resilientmeansoverlying the clamping member and male die and adaptedsimultaneously to exert clamping pressure on the clamping member andshaping pressure on the male die. i t;

2. In a press, a female die having a cavity and arranged to support aplanar metal 'sheet .on its upper surface, a clamping member 4overlyingthe upper surface of said die and adapted to clamp the metal sheetagainst the surface of said die, a rigid male die member fitting withinthe clamping member and of such size and shape .as to substantially llthe space within the female die, and a reciprocable rubber pad movableto simultaneously engage and exert clamping pressure on the clampingmeans and shaping pressure on the male die.

3. Ina press, a female die having an open space and adapted to supportthe rim portion of a. planar sheet of material onvits upper surface, aclamping member overlying the upper surface of said die and adapted toclamp the sheet of material against the surface of said die, a rigidmale die member fitting within the clamping member and of such size andshape as to substantially fill the space withinthe female die, andresilient means reciprocally mounted in said press and operablesimultaneously to engage said clamping member and male die for exertingclamping pressure upon the rim portions ofthe work piece and to engagethe male die for' advancing the same to shape theworkpiece, saidclamping member having areas of varied configuration engaged by saidresilient means for conveying different pressures upon different rimportions of said workpiece.

4. In a press, a female die having a cavity and arranged to support aplanar metal-sheet on its upper surface, a clamping member overlying theupper surface of said die and adapted to clamp the metal sheet againstthe surface of said die, a rigid male die member fitting within theclamping member and of such size and shape as to substantially fill thespace within the female die, and a rubber pad overlying the clampingmember and male die and adapted simultaneously to exert clampingpressure on the clamping member and shaping pressure on the die, the

portion of the clamping member receiving pressure from said rubber padbeing of irregular shape so that different parts of said member aresubjected to different pressures.

PAUL E. FLOWERS.

